Flexibly mounted thermocouple for measuring surface temperature



J. A. OBERMAIER 3 Sheets-Sheefl l Fiid June e, 1942 June 10, Y194W,

FLEXBLY-MOUNTED THERMOCOUPLE FOR MEASURING SURFACE TEMPERATURE NN f Q uwJ. A. oBERMAl-ER June l0, 1947.

y FLEXIBLY-MOUNTED THERMOCOUPLE FOR MEASRING SURFACE TEMPERATURE FiledJune 6, 1942 3 Sheets-Sheet 2 June 10, 1947.

Filed June 6, 1942 5 Sheets-Sheet 3 wfg- 32)? 3.94 A e 3742 Zzz/@ZZLOW-UBM/OA Oermer jy /ww, J ,0m L5..

Patented .lune l0, 1947 UNITED STATES Aram OFFICE FLEXIBLY MOUNTEDTHERMOCOUPLE FOR MEASURING SURFACE TEllPER/ATURE 15 Claims.

This invention relates to improvements in pyrometers.

While the invention is particularly applicable to surface temperaturepyrometers for measuring the temperatures of production machinery andproducts, such, for example, as fly wheels, shafts, heated drums,calenders and the like, and in connecton with plastic molding, diecasting, rubber plants, paper mills, and elsewhere, it is to beunderstood that in its broader aspects the present invention is notlimited to surface temperature pyrometers, but may be embodied in otherpyrometers as suitable and desired.

The present application is a continuation-inpart of my copendingapplication Serial No. 190,721, led February 16, 1938, now Patent No.2,285,457, issued June 9, 1942.

One of the main objects of the invention is to provide a pyrometer whichwill give an accurate and almost instantaneous reading by merelypressing the tip of the thermocouple part of the pyrometer in contactwith the surface of the object, the temperature of which it is desiredto measure, or by merely pushing the tip of the thermocouple into theobject, or, in the case of heat zones, liquids, and molten metal, byplacing the hot junction of the thermocouple therein.

It is a further object of the invention to provide a thermocouple whichwill pick up the temperature to be measured with great speed and which,at the same time, will have the desired strength. This is accomplishedby separating the tip of the thermocouple from the base. The means whichseparates the tip of the thermocouple from its base supports the tip onthe base and is strong, and, at the same time, of minimum mass, so thatthe instant the tip is applied to the object the thermocouple element isheated and an accurate reading is produced. The reduction in massprovides maximum thermal insulation. At the same time, the mass of thetip supporting and separating means is reduced with- ,out sacrificingthe desired strength, and the construction whereby these advantages areobtained is a simple and natural one.

Itis also an object of the invention to provide a thermocouple that isadapted for pivotal attachment, for example, to the outer end of anextension arm, the thermocouple being adapted to be swung about itspivotal support to different angular positions and being interchangeablewith other thermocouples as suitable or desired.

It is a further object of the invention to provide a thermocouple havinga tip or end piece .mounted in a manner to permit the tip or end pieceto accommodate itself, for example, to the surface of the object thetemperature of which it is desired to measure and, more particularly, toprovide a thermocouple in which this is accomplished, for example,either by mounting the tip or end piece, which carries the hot junction,for rocking movement, or by providing a mounting of yielding characterfor the tip or end piece.

A further object of the invention is to provide a thermocouple having atip or end piece provided with a protecting sleeve or skirt.

Another object of the invention is to provide an improved form of hotjunction and, more particularly, an improved form of hot junction havinga hot junction element retained independently of the thermocouple wires,thus permitting the use of relatively fine thermocouple wires with theaccruing advantages thereof.

Further objects and advantages of the invention will be apparent fromthe following detailed description, taken in connection with theaccompanying drawings in which:

Figure 1 is a front elevational View of a pyrometer embodying thepresent invention;

Figure 2 is a fragmentary longitudinal detail section on an enlargedscale taken through the outer end of the extension arm of the pyrometershown in Figure 1 and through the thermocouple mounted on the extensionarm;

Figure 3 is a transverse detail section taken on the line 3 3 of Figure2;

Figure 4 is a transverse detail section taken on the line 4-4 of Figure2;

Figure 5 is a transverse detail section taken on the line 5 5 of Figure2;

Figure 6 is a perspective view of one of the hairpin 01- U-shaped wiresfor supporting the tip of the thermocouple shown in Figures 1 and 2 onthe thermocouple base;

Figure 7 is a perspective View showing another form of thermocoupleembodying the present invention and adapted for use with the instrumentshown in Figures 1 and 2;

Figure 8 is a transverse detail section taken en the line 8-8 of Figure7;

Figure 9 is a side View, partially in longitudinal section, of anotherform of thermocouple embodying the prevent invention;

Figure 1Y0 is a fragmentary detail section taken Aon the line Illl0 ofFigure 9;

Figure 11 is a side View partially in longitudinal section of anotherform of thermocouple embodying the present invention;

" Figure 12 is a view similar to Figure 11 of 'one end the 3 anotherform of thermocouple embodying the present invention;

Figure 13 is a side View of another form of thermocouple embodying thepresent invention;

Figure 14 is a fragmentary view partially in section and showing more indetail the thermocouple shown in Figure 13;

Figure 15 is a transverse section taken on the line |5-I5 of Figure 14;

Figure 16 is a perspective View of the L-shapeclV thermocouple basemember of the thermocouple shown in Figure 2;

Figure 17 is a perspective showing a further form of thermocouple;

Figure 18 is a fragmentary side View showing a thermocouple andcooperating yoke with means for assuring proper applicatlcn of the;Deli@ O the thermocouple to the yoke;

Figure 19 is a fragmentary plan View of the structure shown in Fig-ure18;

Figura 20- is'- a fragmentaryi4 detailv elevation showinganotherarran'gemen-t for assuring` proper Y application or the base` ofthe thermocouple to the yoke.;A

Figure 21 is a detail:l section taken on. the line 24.-.212 of Figure20,` showing in eleva-tion the base cti-the thermocoupleeinpo'sition'in.the yoke.;

and Y Figura 22 is a. fragmentary side7 Viewv of the base ofthe.thermocouple.

Referring novit to. the drawings, the device illustrated in Figure l;comprises an indicator l0 havingan extensiona-rm lll. uponthe endof;which a' plurality. of( dierent types. of thermocouples are. adopted forinteiicha-ngeable: mounting.

The. indicatorv ILE] comprises a metallic casing lili secured tol an:insulating; base 1,8. by screws; 1'9. The casing il serves as. a.housing for a meter which may be; of; any.- convention-al'` galvanometerorlmillz-volt'meter. construction, such, for example, as; the generaltype of? construction shown and described in my PatentA Nn. 1,597,327.;issued August 24, 1193275: The meter includes-,apointer 20 and a painof-sca-leslf and; 22,; '1 -The scale 2l isl calibrated; fprhigh,temperature indications, andtll'ciscale: ZZ-lisea-librated for lowtemperature indications, as, will. hereinafter appear, Each scale 2J;and-22;is graA` tedf in termsof temperature, preferably in; desces.offFahrenheit-. The Qaiig; t7: is Dr-QV- idedi with a. handle .'f`suitably secured, for example, to;the ;b ase i8?,

The. extension arm. I l; campuses atubiilarmetallic member adapted; atone end for rotatable mounting-Qn theiliCl-iatcn I4 d providedwh contactmeans for connectingthe.thermocouple lgad Wires in, Circuit; with; the.indicator, for. example, asmore` fullydisclosed in my Patent No,2,285,452? above referred to.

The lead Wires 36 and 3.1,` whichA electrically connect theVpartiCular-thermocouple mounted Y o-n vthe,outer, endof,` the.extensionY armv Ll, tai-,he indicator` Lil, extendt through the tubulararm. 1,! andare insulated fromthis arm. and-,fromach other irl-anysuitable; or preferred manner. In the illustrated en'ibodir'nent oftheinvention, these Wires (i6 andj, extend through openings gl; 'and` 351ma small diameter insulator 40. which may be formed of porcelainbr othersuitableim Sillatns material.- Thisin'sulator 4' is Sho-wn 0f circularcross sectionA and, extends. substantially throughoutthe lengthofthetubular; arm Il. At l,ires stand 3-1extend out fromthe endortheinsulator andare connected; tothe Contact meansiorterminaiimembers (notshown) on the a-i'm H; which contact meanssorterminal members areadapted for engagement with suitable contact means or terminal memberson the indicator I0.

The outer end of the arm I l is provided with a yoke cr fork 55 forreceiving any of the various types oi thermocouples. This yoke 65comprises, as shown in Figure 2, a pair of L-shaped metallic members 56and 6T having apertured bases 68 and 69 respectively. Thesemembers 66and 61 are assembled and insulated from each other by insulation 1S,which may be mica or other suitable insulation. The adjacent end of thearm H is provided internally with a bushing 1 Iv soldered orotherwiserigidly? secured in place therein. Mica, Bakelita or othersuitable insulation at 72 insulates the base 68 of the L-shaped forkmember 6,5: from the adjacent end of the arm H, and a tubular screw 14headed at 15 passes through the openings in the bases 68 and 69 of thefork members 65 and 61 and has threaded engagement Withthe bushing 'H-tosecure' the fork members rigidly in place on the outer end of the armH?. Insulation atY 1E insulates the, screw 'Ml from the forkAVm'en'ib'er- 6.11. This insulationis! backedbyy a channel-shapedmetallic member 18S, andi the insilla-tion@ 'li and: 181 insulates thememberl 'MP and tl'ieheadl of the screwI 'M fromtheI project-ing legsci1 thefork7 members-l The i-nsuiator 40-passesaxiallylthroughthe-tubularscrew '141,V and the lead Wires 35i andv 3=T` extendifromthe-outer endL ofl the insulatorlland are connected? byscreiivsA8i!" and coopera-ting nut members, one to-each1of the .'Lforlsl members5B-and Sli. Thefork-' thus constitutes not only a fork for mechanicallyvsupport-ingv the various thermocoupl'es; but also a-y fork through whichtirava-11i'- ous thermocouples appliedt thereto. are connectedelectrically to4 the# lead wires 36 and 31. Thiseliminates-thenecessityi for pigtail connections and the like; and' isa` distinct advantage:

The particular thermocoupleV |52 shown applied tothe fork- Bl is` fonmeasuring the temperatures of either metallic ornon-metallic` surfaces,whether the-surface-issoft or hard, clean oncoated'. Itj is` especiallysuitableforplastic or rubber molds; platens, plates, glassware a-nd`walls or other relativelyx flatsurf-aces.l Theunique construction`reduces conduction lossto-a minimum, andvi gives; maximum accuracy;

The` thermocouple Ii21 comprises amounting basecon'sisting ofanL-shapedmetallic member (i22 and ai flat metallic member 8@` insulatedfrom each otherby aL b'er, Bakelita or-other-suit able insulating blockt84i disposed therebetween. Mica or other" suitable insulation at 8'5'insulates theaprturedbaseiotthelmember 82f1'om the ad"- j'acen't end ofthe member 83a The member-82H5 secured" to* theblock- Slli byl screws` 8which are accessible (Figure 5) through openings 81A in the membern 83and which arev applied; to position with'A their heads.- countersunkinioneY side off the block 811i and thereby. insulated from. the memberv831.' The memberl 831s similarlyl securedA to the block 84: from theopposite side. by. screws 88 which are accessible.throughropenings;885inthe membeniBZ'- and. are appli'edto posit-ion with their heads`countersunk; in. the optiositeA sidei of? the block 34A and therebyinsulated' from the-mem,- ber-y 82i.

The therm'oc'ouple` mounting; baseis. pivotaily securedi between theprojecting:- legs.. ofi the fork 65 hypoaxialscrews 9D. ThesescrewsSil'rhave heads attheir` outerP ends. and; adjacent said heads; havecylindricallportions- 9L which nt in 'openingsSZin 'the-projectingl'egsof-tfheforlt 65.

The reduced diameter inner ends of these screws 90 are threaded and havethreaded engagement with correspondingly threaded openings in themetallic members 82 and 83 of the thermocouple mounting base. Phosphorbronze or other suitable washers 90 between the heads of the screws 90and the legs of the fork 65 provide friction tight joints which permitturning movement oi the thermocouple base about the cylindrical portions9| of the screws 90 and frictionally hold the base of the thermocouplein the different angular positions to which it is turned.

The ability of the thermocouple to be turned and held in any angularposition about the common axis of the screws 90, particularly where theopposite end of the extension arm II is adapted to be rotated about thelongitudinal axis of this arm and clamped in any angular position asdisclosed and claimed in the Patent No. 2,285,457, makes it possible toplace the thermocouple unit in any position to contact the heatedsurface and with the front of the indicator I disposed toward theoperator so that the temperature may be ascertained at a glance.

The angular fork member 6B of the yoke 85 is preferably provided with aplus (-l-) marking, and the angular member 82 ofthe thermocouple base islikewise preferably provided with a plus marking indicated at 9B inFigure 16, or the parts are otherwise suitably marked to make sure thatthe thermocouple is properly applied to the yoke 65. If the thermocouplewere applied with its plus (-1-) side in contact with the minus side ofthe yoke 65, the instrument would read backwards.

'I'he tip of the thermocouple I2 comprises a small diameter insulatingtip 98 formed of porcelain or other insulating material which willwithstand the high temperatures to which the device is subjected. 'I'heinsulating tip 98, shown of circular section, is cemented or otherwisesuitably secured in a metallic tip holder 99 of tubular form andprovided with an annular base :Bange |00 at its inner end. A disc IIlIof platinum, gold, or other suitable material secured in place at theouter end of the tip 98, constitutes the hot junction of thethermocouple.

The lead wires |02 and |03 for the thermocouple extend through openingsin the insulating tip 98 and are insulated from one another by this tip.The outer ends of these wires are welded or otherwise suitably joined tothe disc IUI. The wires |02 and |03 pass through openings |05 and |05 ina clamping plate |06 and in the base of the angular member 82, andextend through suitable openings in the insulating block 84 and areturned out or otherwise connected at their opposite ends at |08 and |09,one to the metallic base member 82 and the other to the metallic basemember 83. Thus, when the base member of the thermocouple is applied tothe yoke 85, the contact between the yoke members 66 and 61 and the basemembers 82 and 83 completes the circuit between the wires |02 and |03and the lead wires 36 and 31.

The tip of the thermocouple is supported an appropriate distance fromthe base of the thermocouple by two hairpin or U-shaped wires II5preferably formed of steel wire, piano wire, or the like, so that theywill be of great strength and, at the same time, may be of smalldimension. These wires |I5 conduct very little heat and, at the sametime, they are yieldable to such extent that the thermocouple will adaptitself to the sur- 'face to which it is applied.

In the illustrative embodiment of this form of thermocouple, theU-shaped wires I I 5 are applied with their legs extending throughopenings in the iiange I 00 of the tip holder 99. 'I'he bend I I6between the legs of each wire H5 is held between the ange |00 andshoulders formed by'notches or upset portions II8 in the. externalperiphery of the tubular extension of the tip support. At their freeends the extending legs of the wires VI I5 are turned out at rightangles and these right angle ends |20 are positioned in grooves I2I inthe adjacent face of the L-shaped base member 82, and are clampedtherein by the clamping member |06 which has openings through which thewires II5 extend and an enlarged opening through which the lead wires|02 and |03 extend clear of the clamping member |06. The depths of thegrooves I2I are preferably slightly less than the diameters of the wiresII5, and the clamping member |05 is secured to the L- shaped base member82 by screws |24.

The thermocouple I3 as shown in Figures 7 and 8 is a low temperaturethermocouple for the measurement of low temperature indications on thelow temperature scale 22 of the indicator I0. The means for setting thedevice selectively to indicate on the high and low temperature scales isshown and described in my Patent No. 2,285,457 mentioned above. Thisthermocouple I3 is interchangeable with the thermocouple I2, and itsbase |30, which is similar to the base of the thermocouple I2, isadapted for pivotal attachment to the fork 65 in the manner in which thebase of the thermocouple I2 is applied to this fork.

The tip |32 is formed of ber or other suitable insulation and has anintegral base ange |33 to which the bends of the hairpin or U-shapedwires II5 are secured as in the preceding embodiment of the invention.The out-turned ends of the extending legs of these wires II5 .areclamped in notches |34 in the base member 82' by a clamping member |06as in the preceding embodiment of the invention. A disc |35, formed ofgold or other suitable material and secured in place at the outer end ofthe tip |32, Vconstitutes the hot junction of this thermocouple. Theinsulating block 84 of ber, lava, or other suitable insulating material,corresponds with the block 84 of the preceding embodiment of theinvention.

The thermocouple wires |31 and |38 are brazed or otherwise suitablyconnected to the disc |35 and extend through spaced openings in the tip32 which insulates these wires one from the other. The wires |31 and I38 extend on through openings in the clamping member |06 and in the basemember 82 and through openings in the insulating block 84 and areconnected one to one metallic base member 82 and the other to the othermetallic base member 83 as in the preceding embodiment of the invention.In this case, however, the thermocouple wires |31 and |38 are preferablylooped through openings in the flange |33 of the tip |32 and are therebyanchored at |40 to the base end of the tip.

The thermocouple shown in Figures 9 and 10 is interchangeable with thethermocouples I2 and I3, and its base |50-which is similar to the base I30 of the thermocouple I3 and to the base of the thermocouple I2-isadapted for pivotal attachment to the fork 65 in the manner in which thebases of the thermocouples I2 and I3 vare applied to this fork.

The tip of this thermocouple comprises an insulating tip |5I formed oflava, liber, or other :ganarse suitable. insulating material; A; lara.tip suitable for-the: higher. temperature. ranges', a'. nnerV tip: is:suitable for the. lower` temperature: ranges. The'. insulating; tips|5:|,.w.hich ispreer'-e ablyI or circular crossrlsection; end |252offreduceds diameter which extends intoz' theouter' endi of a tubularextension; |153 on' the: clamping; member or base; part: |:54,v. afndzispivotedwn: a pin [e551 theends oi' are*1 care'd! bythe; outer.' end; ofithe'. tubular extension. |531. 'llheaclampngg member' or' base part|.54i corre.- sponds'.' with the. clamping.' member' or' part Hli" ofthethermocoupleeshowne im Figure. 7. and'. haseimemher. |56; correspondsWitliithe. base. member 82" of. the thermocouple; shown; in Eiga ure7T.. The; opening in' the. inner end.'A of. the'tip" lfiLlthrough. whichthe. pin.. |55 passes'. is;l oi'. a diameter'si'ifflcientlyy largerthan'the. diameter ot tl'reg pin; to: permit. a loose:v pix/totalaction: of the; tip |51v aboutlthe. pinl |55;. thereby makingl the endof the tipse'lfeaccommodatingnfor'exampla. to the: surface thetemperature; ofi which'. it'. s desired to; measure.

Aidse.. |518. of platinum', goidr other? suitable.' material: secured inplace.: at themuter. end'. o thev tip l'l; constitutes; the.' hotjunction. of: the4 ther.- mocouple'.. The thermocouple Wires |59` and'.I'G are. brazed', Welded',. or.' otllervvise;` joined: to', the disc.liandzextend' longitudinally'throughdongie tudinal openings |161.t and.|625. in' thestipeA member as: shown: in. Figure 10; andrfare' connectedat their; opposite: ends,'. for examplato the. metallic basefmember'|e5ii` and the cooperating base inem` ber in; themanneu'shown morein.detaili1r1E.igure 2: The 'portions'of the; Wires' |.59 and. l'? eX-tendihg'. beyond' the'fy innerend of the'. tip: 15| arepreferablycovered with insulation Yas: shown. at

Also-brazedor otherwisesecuredmo thedisc |58 are a secondpairof.wires:|t|l and; ll'which'exe tend; through longitudinali.opern'rrgs:Y |56 andir im the enlargedv outer ends of;the-:tip;.Therinner endsiof the Wiresi |64'an'dt. Iarefturnede out lat:-era'llyf'and: cernentedtat. liiz'or. otherwise secured inv lateralopeningszin; the. tip'.l I5 Ii. The: Wires: 6:.4' and lfmay be braZedor; joined' t'o. thefdisc: |58 anthe'same' time' thatzthe wires land;416.0.: are brazedlor joineditoithedi'se. Thewires: r6.4 and |55constitute; retaining;v Wires, thereby: permit;- ting the use of veryline thermocouplewiitesibe.- cause'. theeA thermocouple wires are notivdepended on'. to: retain thedi'sc'.v |.58f inplace'. This. contri'-butes". to'. reducingy conduction'4 losses to: az; mum; and .thethermocouple.: junctiuna. are. close together to minimizeconduotiornlossthroughithe supporting medium.. In user the' tip |51; and particularlythe; hot junction'. thereoni.. isA selfiacconmiodatinggtathesurflacexthe temperaturefoi whiehzit: is: desired-r tog measurehy loosepivotal movement' of thatip; |51 aboutlthe'pin. |'5.5..

Thee theiinooouple` LlZslioWnmEig; l'l-.hasl the insulating;refra'ctorj/` tip: H3 loosely' pivoted: on apin.'y E .l hina theiouterendofx theatubula-r'extension M inthe. mannen' in; which; the; tip; |51:of the previous? emhndiment. oi'. the' invention ie pivotedonltiepinl'si.

The'. disc: |.'..`|.Gfof:platinum, gold', or'otherfsuitable material..is' secured'. in; place; at the. outer end .of the: tip;L Viliand.`-constitutesf the f hot. junction of lthe thermocouple:Thef'thermo'couplewires and' Ii are bra-zei. Weld'edgor otherwise;joined tuitlie disc: 'iii and'exten'dil ongitudinallyf throughlongitudinal openings in theltipnrnember if'lf-and throughsthe'ftubular': extension' 'll'r and: arerconnetted: attireir oppositeends; forz eXa-mplegtorthe metallichase members ofP the mounting basewhich' is' adapted: to: be mounted irr the yokef at'. the:y outer endfof the: extension` arm: interchangeably' Withr the other thermocouples.`'Eher portions; of. thevwires; and` |"|8 extending be yondt'lfie.linner' andi of" the tip"v |'13f are-r preferably' covered; Witlrinsulation at |82l Retaining, Wires; m4,. similar to.' the. retaining;Wires shown; inY Figure. 9,l arezpreferahly'inrazed: or'otherwiseijoinedr tothe` disc Lloi These'wi'resa |'84l extendthrougirlongitudinaltopenings inthe ext-- larged outer end'. or the.tip: |53; and; theiriinner endsf are, turned; out.' laterally' andcemented at mit" or otherwise*securedin` lateralfI openings |185.inthtip: 1:3. As'inztheemhodiment' ofthe inveIr.- tion' shown 'inFigures.: 9Y and; 10;. the: retaining: Wires' |64' may..1 h'e'hrazedy orjoined.toatlae'disl,` ISLE? at-the same' time'- that' the:tl'i'ermocouple vvutes are: brazen. on joined.:` to t'he.` disc.: The'.wiress |184 retairr the disci l'l'f in' place, andi thereby make it.unnecessaryto retain; thisi disc. iniplace by. the; thernmcouple:Wires.. The. tnermocouple Wires' mamthereforahe. made veryine.: The.'connue--V tion loss in this emhodirnentozthcrinventionf, asf inthe'embodimentshowrr in; EigfuresiQandalU; is reducedto :al minimum,

nectubular extension arm' H5 isshown as'hav.- ing: detacliaoly:nnumted'rthereon, for. example: by afscrew. L9 Bran .annular .'shiel d". m2,'which protects; for. example;.the2 insul ation, screws; .screw` threadsand thelike at themounting base lf'ilofithezthermucoup'le'. from: the*high: temperatures to: Which the not. junctiorro'f. theithermocouple.is.. adapted' tofhe subjected.. Ii'the'h'ead roomis` notflarge enoughfor the operator to pass the shieldliaud reach, his.- worle, the'.shield; |922 mayy loeremoved byflooseningitheJscrev/f" lililf.A

Ai tubular protecting:sleeve IBilLis 'secured-to fthe outer; end? of:the' tubular: extensl'onl arm: |-1'| 5 and has.: ani enlarged outer'end. Which surrounds;` andprotects fthe' tip;V H3 andixtlreeparts.carried thereby; Theendfofthetips |13; andparticularly the discIfirproj ec'ts'endwis'e fromthe end'. of' the=protect ing` sleeve;I'B'Ii for engagement, for'example', vwith the surfaotethe temperature'of! which' it is-desired to-measurezY Pivotal' movementi of thectipA |l3about' the pin |14 permitsth'erend; ofthetip, and particularly thediscorz junction |756; .totagaihst the 'suriacethetemperatureolwhiclita'desired to' measure. even .VJ-here: the. tip. L;A applied;at'. an angletsuch surface: The liotjunction.of the thermocoupleshownfinFig;V l1 is thusselfeaccom'- modating' to.' the surface:y tor which? it.is: applied in the manner in:Whichfthezhotjunction of thethenfnocounle'- shown.- in: Figures: 9' and'. 1.0L is; self'-accommodatingit'o :the surface to 'fwhich'asuchhot junction is. applied.

Theftip.' or hotjunctionl of? the' embodiment'lof tneinvention: shown inl Figures 7.' andi 8;. and: the tip: or: hot junction. ofthe:embodimentY of4 the inventionshown in Eigures 1I' and 2: are-'self-aeonnnodatingto At'hesnrfaces to 4which they' are applieddue to:the-sp'ringiness'zin fth'efwre supp erts for the.' tips` of thesetliermocouples:

In the embodiment of the invention-shownfin Figure-12gthe refractorytip. l96.fis-zlooselypivoted on. a'- pin: |91 carried'fatfits oppositeendshy the tubular extension,armr nnvtheclampingmemf berZwhiehcorrespnnds, fori'example; .withthe c'lampingmember |56? ofthefembodiment-.iof the inventionfshow'n inFigures .'7- and.8J Inrthisem 'bodiment of' the-invention. the tubular protecting sleeve 2m,AisiOrmedv as an.. integral part-.of the outer endfoffthe extensionarm.|98l, andthe-inner end of the tip |96 is reduced in-diametertoex* .9tend into the arm |98 for loose pivotal support on the pin |91. Y

The thermocouple wires 205 are joined to form the hot junction 288 atthe outer end of the tip |96. The hot junction 285 may be formed by awelded or other suitable connection between the thermocouple wires, andthis junction is positioned outwardly of the outer end of the tip or ina recess at the outer end of the tip. Coiled spring portions 288 areprovided in the thermocou-ple wires 285 to provide suitable springtension therein, the longitudinal openings 268 in the tip being formedto receive these coiled spring portions of the thermocouple wires. Thethermocouple shown in Figure 12 is extremely rapid in operation, and thethermocouples with the disc type of hot junction are particularlysuitable for higher temperaturesand where durability is desired andspeed not so important.

The thermocouple 215, shown in Figures 13, 14 and 15, has the refractorytip 216 supported the desired distance from the base 211 by wires 218which preferably converge from the base toward their outer ends. Theouter ends of each pair of these wires are twisted together and turnedout laterally at 219, and a collar 288 is pivotally supported upon theout-turned ends 219 for swinging movement thereon. The base 211 isadapted for pivotal attachment to the fork 85 at the outer end of theextension arm in the manner in which the bases of the otherthermocouples herein disclosed are attached to the fork. The inner endof the tip 216 is reduced in diameter to extend into the collar 280 withadequate clearance therebetween, and has pivotal support in the collar280 upon a pin 28| disposed at right angles to the common axis of theoutturned ends 219 of the wires 218.

A compound pivotal or full swivel support is thus provided for the tip216, which tip is adaptcd to turn in one plane about the pivot 28| andin a plane at right angles thereto about the outturned ends 219 of thewires 218. The lead wires 282 are connected to the hot junction 283 atthe outer end of the tip 216, The hot junction 283 may be formed by awelded or other suitable connection between the thermocouple wires, andpreferably is positioned in a recess 284 in the outer end of the tip218, coiled spring portions 285 being provided in the thermocouple wiresto provide suitable spring tension therein.

The thermocouple 215 is extremely rapid. It provides a reading in threeto ve seconds. The full swiveling of the tip 216 provides forautomatically positioning it against the desired surface. Thiseliminates the necessity and bother of aligning the tip with thesurface.

In eiTect, the wires 218 separate the tip of the thermocouple from thebase, and the size or mass of the thermocouple tip is so small that anexcellent and exceedingly quick pick-up of the temperature to bemeasured is secured. Atv the same time the wires 218 provide a tipsupport which is exceedingly strong and has a minimum mass wherebymaximum thermal insulation is secured. These are important aspects ofthe present invention, because if the size or mass of the parts were toosmall, the desired temperature pick-up would not be secured and, at thesame time, if the tip were not detached from the body of thethermocouple and yet of the desired strength, the device would not besatisfactory.

The thermocouple I4 shown in Figure 17 is a ribbon type thermocouplewhich is made up to nt small and medium diameter cylinders orA curvedsurfaces. Its hot junction is in the form of a Asuitable metallic ribbonwhich is yieldable to the surface to which it is applied. A channeledstop at |5| and spring arms |52 are arranged to support the ribbon |58and to limit the pressure of the same while in contact with therevolving surface to prevent excessive wear.

The base end |53 oi this thermocouple is pivoted at |54 on a mountingmember |55 which, in turn, has threaded openings 56 at right angles tothe axis of the pivot screws |54 for engagement with the screws 90pivotally to support the thermocouple, for example, on the fork 65. Themember is thus capable of being turned and clamped in any angularposition about the common axis of the screws 90, and the member |53 iscapable of being turned and clamped in any angular position about theaxis of the pivot screws |58', which, together, and with the ability ofthe extension arm to be turned and clamped in any angular position, is adistinct advantage in that with these angular movements it is possibleto place the thermocouple in any position to permit it to contact theheated surface with the front of the indicator I8 directed toward theoperator.

In Figures 18l and 19 I have shown means for assuring proper applicationof the base of the thermocouple to the yoke or fork 318 at the outer endof the arm 31| that projects from the indicator. The yoke or fork 310 issimilar to the fork shown in Figure 2, and the base 312'of thethermocouple is similar to the base shown in the same gure except thatthe leg 313 of the fork is wider and longer than the other legl 314, andthe metallic member 315 of the thermocou- .ple base hasa stop 316,thereon. The greater width and lengthof the leg 313 is secured byforming same about a greater radius at the rounded outer end, and thestop may be in the form of a screw having threaded engagement with themember 31.5. The stopy 316Y together with the greater width and lengthof the leg 313 prevents Apositioning the base of the thermocouplebetween the legs 313 and 314 of the fork 310 except with the metallicmember 315 in contact with the leg 314 and the metallic member v318 incontactl with the leg 313 regardless of the angle at which the base ofthe thermocouple is inserted between the legs of the fork 310.

The thermocouple shown in Figure 18 need not be of the needle type asshown, but may befof any other type interchangeable Vwith the otherthermocouples. Its base is pivoted to the fork 318 at 380.

Figures 20, 21 and 22 show another arrangement for assuring properapplication of the base of the thermocouple to the yoke or fork 318. Inthis case, one leg 313 of the fork 310' has a slot 384 opening from theend thereof for receiving the cylindrical portion 385 of one of thepivot screws 38E on the thermocouple base 381, and the other leg 314 hasa, narrower slot 388 opening from the end thereof for receiving thecylindrical portion 389 of the other coaxial pivot screw 398. The largerpivot screw not being engageable in the narrow slot 388, the desiredpositioning of the base of the thermocouple in the fork 318' is assuredbecause assembly is possible only with the thermocouple in properposition,

In practice, the loose pivotal action of the tip |5| about the pin |55(Figures 9 and 10), and the corresponding loose pivotal action of thecorresponding tip members in Figures 11, 12, 13, 14,

ami L5 .about their :piyot pins |14., ,191, and '281, respectively,,permits 'a .more or .less universal movement of the tip .forself-.accommodation .of the hot junction of the thermccouple to .theobject to which the thermocouple .is applied. AWith this provision .itis not necessary for the `user of the device perfectly to align v:thesame with the object to 4which the device iis applied, yet properapplication of the tip the device, and particularly the 'hot junctionlof the .thermocouple to :the object, is assured.

In Figures .'11 :and 1'2 -the hot viunction :is ,shown extending outbeyond the end ofzthe tip. This is particularly adapted `lor lowtemperatures .up -to approximately 860 JF. tures, i. e., temperaturesover 'apprOX-ima'telySOO" F., the hot junction is preferably disposedsub- :stantial'ly lflush with the end of the insulating tip.

In Figure 1 4. hot .junction is :shown lset in within the end of the tipinwardly slightly :of the .outer end .lof the tip.

The coiled spring `portions 208 of the thermo- -couple elements inFigure 12, and the corresponding coiled spring portions 2185 .of .the.thermocouple elements in Figures i3 and 14 4give a :spring action atthe hot junction of the thermocouple. The Icompressibilty 'oi the:spring por-tions provides for better contact .of the hot .junction withthe object when the fthermocouple is applied thereto.

The protecting sleeve' F94 in .Fig-ure ll., and the f protecting .sleeve202 in V.Figure 112 constitute shields V-f'or mechanically protectingthe tips against being oroken for injured `by bumping into or:engagement with another object.

I do not intend to be limited lto the precise .de-

tails shown or described.

I claim:

l. In thermocoup-lev assembly, .a base Vpart comprising a pair ofmetallic base members insulated l.from each other, a support extendingfrom vsaid ibase part, an insulating, tip piucted on said support torturning movement about an axis .spaced from .said base lpart, a metallicdisc at the outer fend onf 'said tip, .a pair fof ithermocouple .wiresjoined to .said disc and extending longitudinal-ly said -tip andconnected in Vcircuit with vsaid base members, and disc retaining wires,joined :to and retaining said `disc -at their outer ends and havingtheir 'inner ends turned Ilaterally and cemented-in said ti-p.

2. A thermocouple assembly comprising a lbase, an insulating tip having-a portion exposed '.-for a-pplication to .fa not object, fa pa-ir ofthermoccuple elements insulated from :each other adjacent said base andextending from said base toV said .and ,jo-ined to form :a 'thermal,junction :adjacent -the exposed portion :of fsa-id tip, and relativelyslender Wire-like means vcarried by `extending from said Abase .andsupporting said tip in position .spaced rom said base :independently ofsaid thermocouple elements and whereby thermally fito :insulate itl-ietip from 'the base.

.3. .A thermocouple assembly comprising :a base, an insulating iti-phaving-.a portion exposed :for application to a hot-object, a pair ofther-mocouple .elements insulated 4from reach other adjacent said ibaseand :extending f'rorn said base to said tip and joined to `form ;a:thermal nncton adjacent :the exposed nounou off .said tip, andrelatively slender Wfires'like'ineans carried .fby and extending fromsaid base and supporting said tip in position spaced fromsaid baseindependently :oi :said ther- -mocouple :elements and Whereby thermallyto :in- 'sula'te the tip from the base part, said Wire-.like tip.supporting Imeans permitting :self-accommo- For .higher tempera- 12dationofsaid .tip to the object to which the thermocouple is applied.

4. A t'hermocouple assembly comprising a base, an Yinsulating tip having`a portion exposed for application to a Ahot object, :a 'pair ofthermocouple elements insulated from each other ad- `jacent #said baseand extending from said base to said tip and joined Vto form .a thermaljunction .adjacent the exposed lportion of said tip, and a plurality ofrelatively .slender Wires extending longitudinally and in spacedrelation from said ibase and supporting said tip in vposition spacedfrom said baseindependently of said thermocouple elements and wherebythermally to insulate the tip from the base part.

5. A thermocouple assembly comprising a pair of metallic base Amembersinsulated from `each other and .adapted for connection in circuit withan indicator, an insulating tip `having `a portion exposed -forapplication to a :hot fob'ect, a pair of ltherm'ocouple elementsinsulated from @each .other .adjacent said base members and extendingEr-.om `said :base members to said .tip and joined to for-m a thermaliftmcti'on adjacent the exposed portion of the tip and connecte'd'zi-n:circuit With :the v.respective base vmembers, :and ,a plurality oflrelatively s'lender Wires extending 'longitudinally .and .spacedrelation .from said :base members :and supporting said 4tip position:spaced `from said ibase members independently oiisaidthermocoupleelements and Wheneby thermally fto .insulate the .tip from the basemembers.

"6.. A ilhermocouple Vassembly comprising a pair -oi metallic `base:members insulated trom each other and adapted if or connection incircuit with .an indicator, an insulating ltip leaving -ja portionexposed for application to a hot object, a pair of thermocouple elementsinsulated -from each :other adjacent said base members .and extend-ingfrom said base members to said tip and yjoined to :form a thermal`junction :adjacent the exposed portion of the tip :and :connected inrcircuit with the respective base members, 'and a v:plurality foirelatively slender AWi-res extending longitudinally .and :spacedrelation from :said base members and supporting fsaid tip in :posit-ion:spaced from :said base `members independent-1y :of said ther- -mocoupleelements fand whereby :thermally to -in- :sulate the tip from the basemembers, :said tip support-ing permitting self-accommodation of said tiprt-o the-robliect [to the thermov'couple is applied.

"7. A thenmocouple assern'oty comprising `a pair yof `metallic basemembers insulated from each other and adapted Jfor .connection inI.circuittv-itl'i an indicator, a :tip fof' relatively :small -mass andexposed for application to fa hotfobject, a 'tip supporting part Vjoinedto said tip, relatively slender wire-like means carried 4by YandIextend-ing from said lbase members .and y'secured `to .said tip'supporting part jto vsupport said tip `.and tip supporting part inposition spaced from said base members vyvlfiereby thermally to insulate`sai-d tip from the base members, and a pair of vther-mocouple elementsjoined -to form a thermal junction adjacent the exposed portion of thetip 'and extend- 'ing through the space .between the tip and the basemembers .and `,connected in circuit with the respective `base members.

y8. A thermocouple .assembly :compri-sing a pair of metallic base.members insulated from each other .and adapted Vfor connection lincircuit with an indicator, a tip -of relatively small ni-ass and exposedtor :application to .a hot liobject, a .tip llpprll'ng .parli dined tosai-fd tip, :a pair Tor relatively slender U-shaped wires having thelegs thereof secured to said base members and extending from said basemembers with the bends between the legs of the wires secured to said tip`supporting part to support said tip and tip supporting part in positionspaced from said base members whereby thermally to insulate the tip fromthe base members, and a pair of thermocouple elements joined to form athermal junction adjacent the exposed portion of the tip and extendingthrough the space between the tip and the base members and connected incircuit with the respective base members.

9. A thermocouple assembly comprising a pair of metallic base membersinsulated from each other and adapted for connection in circuit with anindicator, an insulating tip of relatively small mass and having anouter end exposed for contact with a hot object, a tubular tip holdersupporting said tip, relatively slender wire-like means carried by andextending from said base members and secured to said tip holder tosupport said holder and tip in position spaced from said base memberswhereby thermally to insulate the tip from the base members, and a pairof thermocouple elements joined to form a thermal junction adjacent theouter end of the tip and extending through the space between the tip andthe base members and connected in circuit with the respective basemembers.

10. A thermocouple assembly comprising a pair of metallic base membersinsulated from each other and adapted for connection in circuit with anindicator, relatively slender wire-like means carried by and extendingfrom said base members, a tip supporting part pivoted on the outer endof said wire-like means and supported by said wire-like means inposition spaced from the base members whereby thermally to insulate thetip supporting part from the base members, a tip pivotally supported onsaid tip supportingpart and exposed for application t a hot object, anda pair of thermocouple elements joined to form a thermal junctionadjacent the exposed portion of the tip and extending through the spacebetween the tip and the base members and connected in circuit with therespective base members.

11. A thermocouple assembly comprising a pair of metallic base membersinsulated from each other and adapted for connection in circuit With anindicator, relatively slender wire-like means carried by and extendingfrom said base members, a tip having generally swivel support on theouter end of said wire-like means and held by said wire-like meansspaced from the base whereby thermally to insulate the tip from thebase, said tip having a portion exposed for Contact with a hot object,and a pair of thermocouple elements joined to form a thermal junctionadjacent the exposed portion of the tip and extending through the spacebetween the tip and the base members and connected in circuit with therespective base members.

12. A thermocouple assembly comprising a pair of metallic base membersinsulated from each other and adapted for connection in circuit with anindicator, a tip of relatively small mass and exposed for application toa hot object, a tip supporting part joined to said tip, relativelyslender wire-like means carried by and extending from said base membersand secured to said tip supporting part to support said tip and tipsupporting part in position spaced from the base members wherebythermally to insulate the tip from the base vmembers,and a pair ofthermocouple elements joined to form a thermal junction adjacent theexposed portion of the tip'and extending through the space between thetip and the base members and connected in circuitwith the respectivebase members, said thermocouple elements having coiled portionsproviding spring tension elements therein. ,V

13. A thermocouple assembly comprising a base, an insulating tip havinga portion exposed for application to a hot object, a metallic disccarried on the exposed portion of the tip, a pair of thermocoupleelements insulated from each other ad- 4jacent'said'base and extendingfrom the base through said tip and joined to said disc to form a thermaljunction adjacent the exposed portion of the tip, and a plurality ofrelatively slender wires extending longitudinally and in spaced relationfrom said base part and supporting said tip in position spaced from thebase independently of said thermocouple elements and whereby thermallyto insulate the tipfrom the base.

14. In a device of the class described, in combination, a base, tipsupporting means extending from said base, a tubular tip supportingmember pivoted on said tip supporting means for free tilting movement inposition spaced from said base, an insulating tip coaxial with said tipsupporting member, said insuiating tip having a portion thereofextending into and pivoted within said tip supporting member for freepivotal movement at substantially right angles to the pivotal movementof said tubular tip supporting member on said tip supporting means, anda pair of thermocouple elements joined to form a thermojunction adjacentthe outer end of said tip.

15. In a device of the class described, in combination, a base, a pairof wires carried by and extending from said base and having their outerends turned out laterally, a tubular tip supporting member pivoted onthe laterally outturned ends of said wires, an insulating tip coaxialwith said tip supporting member, said insulating tip having a portionthereof extending into and pivoted Within said tip supporting member forfree pivotal movement at substantially right angles to the pivotalmovement of said tubular tip supporting member on the outturned ends ofsaid wires, and a pair of thermocouple elements joined to form athermojunction adjacent the outer end of said tip.

JOHN A. OBERMIAIER.

REFERENCES ClTED lThe following references are of record in the file oithis patent:

UNITED STATES PATENTS Number Name Date 846,998 Hammond Mar. 12, 19072,022,515 Orchard Nov. 26, 1935 2,142,677 Parker Jan. 3, 1939 2,282,441Whitlock May 12, 1942 1,883,444 Albert Oct. 18, 1932 1,936,140 ObermaierNov. 21, 1933 1,552,284 Evins Sept. 1, 1925 1,553,789 Moeller Sept. 15,1925 1,612,897 Zethmayr Jan. 4, 1927 1,648,942 Hayman Nov. 15, 19272,035,995 Sturges Mar. 31, 1936 2,156,853 Huggins May 2, 1939 2,317,168Ball Apr. 20, 1943 Re. 14,243 Bristol Jan. 9, 1917 (Other references onfollowing page) Number Number UNIT-ED STATES zPA'SIiH'IS Name DateHayman New 1.5, 19257 `Messrs June .6, 1939 vSt01Te1-e1',.al .July 1.1,1944 lStapleton fApr. v14, ,19,42 Homan rJune 15, -1920 Volk-ath Oct.30, `1934 'FoREGN "PATENTS Country V `|I)a.'te GreatrBrta'n Apr. 5,19.40 Great Britain Dec. 2, 1920 Great'ritain O ct. 16, 1940 Aug-ust1923,41. 844.

. 'OTHER REFERENCES Spear :et al., ,Industrial Aand Eng. Chemistry,

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P yrometer lnstyco., Instruments, `v01. `8 (41935,),

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Pyrometer Inst. 1CD., Instruments, April, r1.936, p. 93. (CopyinsaLibr.)

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